Optical detector, picture-recording device and manufacturing method

Abstract

In one embodiment, the optical detector (1) comprises: - an aperture sheet (3) comprising a first layer (31) and a second layer (32), - a plurality of first sensors (21) at the second layer (32), and a second sensor (22) also at the second layer (32), wherein - for each one of the first sensors (21) there is a first aperture (41) and a second aperture (42) in the first layer (31) and in the second layer (32), respectively, so that for each one of the first sensors (21) there is an aperture stack (44) defining a direction of sensitivity (C) of the respective one of the first sensors (21), and - the second sensor (22) has lines of sight (S) through at least one of the first apertures (41).

Description

[0001] Description

[0002] OPTICAL DETECTOR, PICTURE-RECORDING DEVICE AND MANUFACTURING

[0003] METHOD

[0004] An optical detector and a picture-recording device comprising such an optical detector are provided . A method for manufacturing such an optical detector is also provided .

[0005] Document WO 2023 / 006631 Al refers to a sectional multispectral sensor with optical blurring .

[0006] A problem to be solved is to provide an optical detector that has a reduced si ze .

[0007] This obj ect is achieved, inter alia, by an optical detector, by a picture-recording device and by a manufacturing method as defined in the independent patent claims . Exemplary further developments constitute the sub ect-matter of the dependent claims .

[0008] For example , the optical setup described herein is for flicker detection in a multiple-aperture facet eye sensor used in a smart phone .

[0009] According to at least one embodiment , the optical detector comprises an aperture sheet . The aperture sheet has a first layer and a second layer . For example , the first layer and the second layer are made of an opaque material or of an opaque layer sequence . That is , in locations where the opaque material or the opaque layer sequence is present , the first layer and the second layer are lightproof . According to at least one embodiment , the first layer and the second layer, respectively, comprise a plurality of first apertures and of second apertures . For example , the first apertures and the second apertures are holes in the opaque material or the opaque layer sequence of the first layer and the second layer . Thus , light can travel through the first apertures and the second apertures .

[0010] According to at least one embodiment , the optical detector comprises one or a plurality of first sensors . The first sensors are light-sensitive and are , for example , photo diodes . It is possible that each one of the first sensors is a single-channel photo sensor . The first sensors may be based on silicon .

[0011] According to at least one embodiment , the optical detector comprises one or a plurality of second sensors . The at least one second sensor is light-sensitive and is , for example , a photo diode . It is possible that the at least one second sensor is a single-channel photo sensor . The at least one second sensor may be based on silicon, too .

[0012] According to at least one embodiment , for each one of the first sensors there is at least one first aperture and at least one second aperture in the first layer and in the second layer, respectively . Especially, there is exactly one first aperture and one second aperture per first sensor .

[0013] According to at least one embodiment , for each one of the first sensors the assigned first aperture and the assigned second aperture define an aperture stack . By means of the aperture stack, a direction of sensitivity of the respective one of the first sensors is determined . Thus , the aperture stack may in analogy be seen as a tube or cone pointing along the direction of sensitivity, and through the tube or cone light can arrive at the respective first sensor .

[0014] According to at least one embodiment , the second sensor has lines of sight through one or a plurality of the first apertures . That is , light can arrive at the second sensor through the at least one first aperture , for example , exclusively through the at least one first aperture .

[0015] In at least one embodiment , the optical detector comprises :

[0016] - an aperture sheet comprising a first layer and a second layer,

[0017] - a plurality of first sensors at the second layer, and

[0018] - a second sensor also at the second layer, wherein

[0019] - for each one of the first sensors there is a first aperture and a second aperture in the first layer and in the second layer, respectively, so that for each one of the first sensors there is an aperture stack defining a direction of sensitivity of the respective one of the first sensors , and

[0020] - the second sensor has lines of sight through at least one of the first apertures ; optionally, the second sensor has a light entrance face and has lines of sight through at least one of the first apertures and has a line of sight perpendicular with the light entrance face .

[0021] With the optical detector described herein, ambient light sensing and white balancing is possible , especially using flicker detection . The optical detector may be used, for example , in a portable device like a smart phone or a photo camera or a video camera . The second sensor can ef ficiently be used in particular in an optical detector having sectored color sensitivity of a spectral sensor based on facet eye optics made of multiple apertures .

[0022] The accuracy of color and spectral measurement depend, inter alia, on a synchrony signal integration over a source frequency . Therefore , the second sensor is integrated as an additional detector to detect a flicker frequency of the at least one scenery source . Because of sector overlapping and blur in an optical path, segments information about a source flicker is not relevant in every case . Flicker conditions of all segments at once are interesting to set all measurement channels of the spectral detector, that is , the second sensors , to same integration times .

[0023] The si ze and cost of multi zone color and spectral sensor configurations are mainly driven by the number of segment zones and the number of colors , that is , the number of spectral channels . For example , i f there is space for twelve spectral channels having nine directions each, then for increased performance all available channels are better to be used as spectral channels instead of spending one of those channels for flicker detection . Therefore , an optical setup is needed that enables collection of light from all sectors . Due to analyzing only the time information for flicker analysis , the exact angular power distribution is not that important .

[0024] The optical detector described herein uses parasitic cross talk ef fects to enable an overall flicker detection that covers , for example , a full scenery within a field of view, FOV, and that does not increase the si ze and cost of the device .

[0025] Because of a refractive index of glass or another carrier for the aperture sheet , a maximum possible angle of detection is limited to about 40 ° . Aperture areas of mid and bottom aperture layers between arrays of first sensors of spectral channels have no optical relevance for the spectral sensitive facet eye detection . This area can be used to detect a cross talk signal with j ust one additional spectrally unfiltered second sensor, for example . Hence , the additional detector without filter, that is , the second sensor, can collect light passing corner apertures of the upper, first layer of the aperture sheet . At optimi zed aperture layer design, this can cover and overlap the full segment FOV of all segments of the color channel with j ust one second sensor .

[0026] By having such an optical detector, costs can be saved, and device si ze does not need to increase because no additional area in the system is needed for flicker detection . All optical channels are available for improving spectral performance . Full covering and overlapping of scenery FOV with one detector is enabled . For example , only one modulator for flicker processing is needed . Parasitic ef fects and otherwise unused aperture areas in between the spectral channels can be used for flicker detection .

[0027] Thus , the optical detector described herein may be used as an ambient light sensor, ALS for short .

[0028] According to at least one embodiment , there is exactly one of the aperture stacks per first sensor . Thus , there can be a one-to-one assignment between the first sensors and the aperture stacks .

[0029] According to at least one embodiment , for each one of the first sensors there is a color filter . There can be a plurality of the color filters . It is possible that the first sensors are arranged in groups or arrays and that each one of the first sensors of the respective group or array is assigned the same color filter . Thus , each group or array could be sensitive in a same spectral range which is , for example , a sub-range of the visible spectral range . For example . The visible spectral range is from 400 nm to 780 nm .

[0030] According to at least one embodiment , each one of the first sensors is sensitive only in a sub-range of the visible spectral range . For example , there are at least three or at least five and / or there are at most 36 or at most 20 or at most twelve of the sub-ranges . The sub-ranges can be di f ferent in pairs and7or may be disj unct so that the subranges do not overlap . Otherwise , at least some of adj acent sub-ranges may spectrally overlap . It is possible that the sub-ranges or some of the sub-ranges are adj usted to spectral sensitive ranges of a picture-recording device the optical detector is configured for or is built in .

[0031] According to at least one embodiment , the second sensor is sensitive in the overall visible spectral range and / or in the overall spectral sensitive range of an associated camera system . Thus , contrary to the first sensors , the second sensor may not have any distinct spectral selectivity in the visible spectral range . According to at least one embodiment, the second sensor is configured to produce a time-dependent flicker signal. That is, the second sensor is configured to record a timedependent intensity signal. For example, a sample rate of the second sensor is at least 1 kHz or at least 0.1 MHz or at least 1 MHz or at least 10 MHz. Thus, the second sensor may detect 50 Hz or 100 Hz flicker, or 60 Hz or 120 Hz flicker, of artificial light sources like bulbs or fluorescent lamps or also kHz or MHz flicker of artificial light sources like light-emitting diodes, LEDs, driven by pulse width modulation, PWM, for example.

[0032] According to at least one embodiment, the optical detector further comprises one or a plurality of detection timers. The at least one detection timer is configured to synchronize detection time intervals of the first sensors with the flicker signal. That is, for example, if there is 50 Hz flicker detected by means of the second sensor, the detection time intervals of all the first sensors are set to a multiple of a period time of the flicker. In other words, for the detection time intervals Td, the flicker frequency f and a natural number n larger than or equal to one it may apply: Td = n / f. If there is a plurality of flicker frequencies, the lowest flicker frequency may be chosen for the aforementioned formula, or n may be chosen so that Td is an integer multiple of all or some of the flicker frequencies. This may apply, for example, with an uncertainty of at most 1 ms or of at most 0.1 ms or of at most 0.01 ms, for example.

[0033] According to at least one embodiment, the first layer is free of an aperture exclusively for the second sensor and not being part of at least one of the aperture stacks. Hence, the second sensor can have lines of sight exclusively through the at least one of the first apertures . In other words , concerning the first layer the second sensor may exclusively use one or a plurality of the first apertures .

[0034] According to at least one embodiment , the second layer comprises a flicker aperture . The flicker aperture may exclusively be assigned to the second sensor . I f there is a plurality of the flicker apertures and the second sensors , there can be a one-to-one assignment between the flicker apertures and the second sensors .

[0035] According to at least one embodiment , the flicker aperture partially covers a light entrance face of the assigned second sensor, seen in top view of the light entrance face . For example , seen in top view, the flicker aperture is surrounded all around by part of the light entrance face . That is , the flicker aperture may completely lie within the light entrance face , seen in top view .

[0036] For example , the light entrance face is that part of a main side of the second sensor which is sensitive to light . Hence , light arriving at the light entrance face is purposefully converted into an electrical signal . It is possible that said main side have an edge area surrounding the light entrance face , the edge area being insensitive for impinging light so that from light arriving at the edge aera, no electrical signal is produced .

[0037] According to at least one embodiment , the light entrance face of the second sensor partially overlaps with the at least one of the first apertures defining the lines of sight of the second sensor, seen in top view of the light entrance face . In other words , the light entrance face is partially free of the opaque material or the opaque layer sequence the first layer of the aperture sheet is made of . Thus , there can be a line of sight perpendicular with the light entrance face . The light entrance face may be in parallel with the first layer and / or with the second layer .

[0038] According to at least one embodiment , the aperture sheet comprises one or a plurality of intermediate layers . The at least one intermediate layer is located between the first layer and the second layer . The at least one intermediate layer is made , too , of the opaque material or the opaque layer sequence the first layer of the aperture sheet is made of , for example .

[0039] According to at least one embodiment , the intermediate layer or each one of the intermediate layers comprise ( s ) an intermediate aperture exclusively assigned to one of the aperture stacks . That is , for each one of the aperture stacks there can be an intermediate aperture in each one of the intermediate layers .

[0040] According to at least one embodiment , the intermediate layer or each one of the intermediate layers comprise ( s ) an additional flicker aperture exclusively assigned to the second sensor . That is , the additional flicker aperture does not belong to one of the aperture stacks but is separate from them .

[0041] According to at least one embodiment , the additional flicker aperture ( s ) of the intermediate layer ( s ) and the flicker aperture of the second layer are congruent , or the flicker aperture is larger than the additional flicker aperture ( s ) . The term ' larger' may refer to an area content of the respective apertures .

[0042] According to at least one embodiment , there is the exactly one intermediate layer . Alternatively, there is a plurality of the intermediate layers , like two or three of the intermediate layers .

[0043] According to at least one embodiment , each one of the aperture stacks widens in a direction away from the second layer . That is , the apertures become larger along the direction of sensitivity and away from the second layer, that is , towards the first layer .

[0044] According to at least one embodiment , the first sensors are arranged in a plurality of arrays . For example , each one of the arrays being sensitive for a speci fic color and including some of the first sensors . That is , each one of the arrays may correspond to a color channel being sensitive in the respective sub-range of the visible spectral range .

[0045] According to at least one embodiment , a number of the first sensors in each one of the arrays is the same as a number of the directions of sensitivity of the respective one of the arrays . That is , for example , each one of the first sensors in the respective array is sensitive in the same spectral range but the first sensors are for di f ferent directions of sensitivity . It is possible that not two directions of sensitivity are the same within each one of the arrays .

[0046] It is possible that all the arrays have the same set of directions of sensitivity . That is , in terms of directions of sensitivity all the arrays can be the same , but the arrays have di f ferent sub-ranges they are sensitive in . According to at least one embodiment, a distance between adjacent ones of the first sensors within the arrays is smaller than a distance between adjacent ones of the arrays, seen in top view of the second layer. In other words, the first sensors are closer to one another than the arrays.

[0047] According to at least one embodiment, the second sensor is located between the arrays. For example, the distance between the arrays is chosen to be a minimum distance, that is, a distance so that the first apertures of the adjacent first sensors of different arrays do not touch. Hence, between these first apertures there is still some of the opaque material or the opaque layer sequence the first layer is made of. For example, the distance between said first apertures is at least 30 pm or is at least 90 pm. Alternatively or additionally, said distance is at moat 0.5 mm or is at most 0.2 mm.

[0048] According to at least one embodiment, the number of the first sensors in each one of the arrays is at least four or is at least nine. Alternatively or additionally, said number is at most 36 or is at most 25 or is at most 16.

[0049] According to at least one embodiment, the optical detector comprises a plurality of the second sensors. For example, there are at most ten or at most five of the second sensors. Either separate second sensors or a segmented second sensor having electrically separately readable segments read on the term 'plurality of the second sensors' .

[0050] According to at least one embodiment, some or all of the second sensors have pairwisely different directions of sensitivity. Hence, there can be a plurality of directions of sensitivity concerning the flicker detection.

[0051] According to at least one embodiment, the aperture sheet comprises a continuous, hole-free base body. The first layer and the second layer are applied on main sides of the base body, for example. The base body is, for example, a glass sheet or a plastics sheet.

[0052] If there is at least one of the intermediate layers, then the base body can be a laminate of sub-sheets, the intermediate layers being applied between the sub-sheets. Hence, the intermediate layers can be located within the base body.

[0053] According to at least one embodiment, the base body has a refractive index of at least 1.4 or of at least 1.5 and / or of at most 1.8 or of at most 1.7. This applies, for example, for a wavelength of 532 nm and a temperature of 300 K.

[0054] An overall thickness of the base body is, for example, at least 0.2 mm and / or at most 2 mm or at most 1 mm. A thickness of the sub-sheets is, for example, at least 50 pm or at least 150 pm and / or at most 450 pm or at most 320 pm.

[0055] A picture-recording device is additionally provided. The picture-recording device includes an optical detector as indicated in connection with at least one of the above-stated embodiments. Features of the picture-recording device are therefore also disclosed for the optical detector and vice versa .

[0056] In at least on embodiment, the picture-recording device comprises one or a plurality of the optical detectors. Moreover, the picture-recording device comprises one or a plurality of camera systems , the at least one camera system is configured to take pictures in the visible spectral range , like photos and / or videos . Further, the picture-recording device comprises one or a plurality of processing units . The at least one processing unit is configured to calculate a white balancing for the pictures taken by the camera system by using data from the at least one optical detector .

[0057] A method for manufacturing the optical detector is further provided . By means of the method, an optical detector module is produced as indicated in connection with at least one of the above-stated embodiments . Features of the optical detector and of the picture-recording device are therefore also disclosed for the method and vice versa .

[0058] In at least on embodiment , the manufacturing method for producing the optical detector comprises the following steps :

[0059] A) providing a substrate carrying the first sensors and the second sensor,

[0060] B ) providing the aperture sheet having the first layer and the second layer, and

[0061] C ) attaching the aperture sheet at the substrate .

[0062] Step C ) is carried out after steps A) and B ) . Steps A) and B ) may be carried out in the stated order, in reversed order or simultaneously .

[0063] An optical detector, a picture-recording device and a manufacturing method described herein are explained in greater detail below by way of exemplary embodiments with reference to the drawings . Elements which are the same in the individual figures are indicated with the same reference numerals . The relationships between the elements are not shown to scale , however, but rather individual elements may be shown exaggeratedly large to assist in understanding .

[0064] In the figures :

[0065] Figure 1 is a schematic top view of an exemplary embodiment of a picture-recording device with an optical detector described herein,

[0066] Figure 2 is a schematic partial cross-sectional view of the picture-recording device of Figure 1 ,

[0067] Figure 3 is a schematic representation of optical properties of the picture-recording device of Figures 1 and 2 ,

[0068] Figure 4 is a schematic top view of a modi fied optical detector,

[0069] Figure 5 is a schematic cross-sectional view of the modi fied optical detector of Figure 4 ,

[0070] Figure 6 is a schematic top view of an exemplary embodiment of an optical detector described herein,

[0071] Figure 7 is a schematic cross-sectional view of the optical detector of Figure 6 ,

[0072] Figure 8 is a schematic cross-sectional view of an exemplary embodiment of an optical detector described herein,

[0073] Figure 9 is a schematic top view of an exemplary embodiment of an optical detector described herein, and Figure 10 is a schematic block diagram of an exemplary embodiment of a manufacturing method for optical detectors described herein .

[0074] Figures 1 and 2 illustrate an embodiment of a picturerecording device 10 . For example , the picture-recording device 10 is a smart phone . The picture-recording device 10 comprises a camera system 11 and an optical detector 1 . The camera system 11 and the optical detector 1 may be located under a cover glass 13 , for example . Moreover, the picturerecording device 10 includes a processing unit 12 .

[0075] The camera system 11 has a field of view FOV around a viewing direction P of the camera system 11 , the viewing direction P can be an optical axis . It is noted that the camera system 11 is illustrated only very schematically so that components of the camera system 11 , like lenes , optical filters , a CCD chip, or electronics are not shown . For example , the camera system 11 is configured for taking pictures and for recording videos .

[0076] The optical detector 1 is a multi-spectral detector, that is , the optical detector 1 is sensitive in a couple of sub-ranges of the visible spectral range . Thus , the optical detector 1 can be an ambient light sensor, ALS , used for white balancing the camera system 11 .

[0077] Moreover, the optical detector 1 has a field of detection FOD around a viewing direction D of the optical detector 1 .

[0078] Again, the viewing direction D can be an optical axis . For example , the field of detection FOD is larger than the field of view FOV . Hence , the field of detection FOD can have an opening angle larger than an opening angle of the field of view FOV . According to Figure 2 , the viewing direction P of the camera system 11 and the viewing direction D of the optical detector 1 are colinear, however, in principle there can also be an angle between the viewing directions D, P . The field of detection FOD and the field of view FOV are also illustrated in Figure 3 . For example , the field of view FOV is of rectangular shape or of approximately rectangular shape . The field of detection FOD is composed of areas A of color detection . For example , the areas A are of circular shape or of elliptic shape in a plane perpendicular to the viewing direction D of the optical detector 1 . For example , there are 3 x 3 of the areas A. Along a diagonal of the field of detection FOD, there may be the areas Al , A2 , A3 corresponding to directions 01 , 02 , 03 of sensitivity around and / or colinear with the viewing direction D of the optical detector 1 . Because the field of detection FOD is larger than the field of view FOV of the camera system 11 , an ef ficient white balancing across the overall field of view FOV is enabled .

[0079] In Figures 4 and 5 a modi fied optical detector 9 is shown . The modi fied optical detector 9 has a plurality of arrays 25 . In each one of the arrays 25 , there is a plurality of first sensors 21 . Each array 25 is sensitive in a speci fic spectral sub-range of the visible spectral range . The respective subrange can be adj usted by using color filters 51 , like Bragg- filters or tinted filters .

[0080] For example , there are at least three or at least six of the spectral sub-ranges and / or there are at most 36 or at most 25 or at most 16 of the spectral sub-ranges . By way of example , according to Figure 4 there are twelve of the arrays 25 that could be assigned to purple, purplish blue, greenish blue, blue-green, green, yellowish green, yellow green, yellow, yellowish orange, orange, red, and purplish red, for example, compare the CIE chromaticity diagram for identifying the colors. Hence, a number of the arrays 25 may correspond to a number of colors, also referred to as color channels.

[0081] Each array 25 comprises a plurality of first sensors 21 which are, for example, photo diodes based on silicon. Each first sensor 21 may be a single-channel detector. The first sensors 21 are covered by a common color filter 51, however, there can be individual color filters 51 as well. No two first sensors 21 have a same direction of sensitivity C. Hence, a number of the different directions of sensitivity C can correspond to a number of the first sensors 21 in the respective array 25. It is possible that all the arrays 25 have a same set of directions of sensitivity C so that the arrays 25 may differ only in their spectral sensitivity but not in their spatial sensitivity.

[0082] As illustrated in Figure 5, the directions of sensitivity C are defined by means of an aperture sheet 3. The aperture sheet 3 comprises a continuous base body 30. For example, the base body 30 is made of a material transmissive in the visible spectral range, like a glass or a plastics like polycarbonate or poly (methyl methacrylate) . An overall thickness of the base body 30 is, for example, at least 0.1 mm and / or at most 1 mm. The base body 30 can be a mechanical flexible foil or can also be a rigid body.

[0083] The aperture sheet 3 further comprises a first layer 31 and a second layer 32 applied on opposite main sides of the base body 30, respectively. The layers 31, 32 are made of an opaque material, like black chrome, or of an opaque layer stack, like a Bragg-layer sequence possibly containing absorbing materials like silicon.

[0084] In the first and second layers 31, 32, there are first apertures 41 and second apertures 42, respectively. For example, the apertures 41, 42 are of round shape. Visible light can travel through the apertures 41, 42. All the apertures 41, 42 assigned to a specific one of the first sensors 21 constitute an aperture stack 44. Per aperture stack 44, there is exactly one first sensor 21 and vice versa. By means of the aperture stacks 44, that is, by means of the positions of the apertures 41, 42 relative to one another, the directions of sensitivity C are determined.

[0085] As can be seen in Figure 5, at a top face of the aperture sheet 30 next to the first layer 31 and remote from the first sensors 21, optical refraction occurs. As a refractive index of the base body 30 is about 1.5, for example, a maximum angle of incident into the base body 30 is about 40° due to total reflection occurring at larger angles of incident.

[0086] To compensate for a possible dependency of a transmission through the color filters 51 on an angle of incident, optionally there can be a diffusor 55. For example, the diffusor 55 is a matrix material with embedded lightscattering particles and / or a light-transmissive layer having one or two roughened main sides.

[0087] Optionally, the first sensors 21 are arranged on a substrate 53, like a circuit. For simplicity of the drawing, no electrical wiring is shown in the figures. For example, the substrate 53 is attached to the aperture sheet 3 with an adhesive 54, like a transparent glue. Otherwise, if no substrate 53 is present, the first sensors 21 may be attached to the aperture sheet 3 individually or the color filters 51 and / or the diffusor 55 may serve as a carrier for all of the first sensors 21 or for groups of the first sensors 21.

[0088] Otherwise, the same as to Figures 1 to 3 may also apply to Figures 4 and 5, and vice versa.

[0089] For example, if ambient light is based on an artificial light source, then the ambient light may be provided with a periodicity, like 50 Hz. Such a periodicity of the ambient light may also be referred to as flicker. If the first sensors 21 are not synchronized with the frequency of the artificial light source, then the color measurement of the ambient light may be adulterated, and white balancing may be hampered. Therefore, for accurate white balancing a flicker detection is required. However, a flicker sensor can potentially lead to additional space requirements and, thus, costs. By having the flicker sensor of the optical detector 1 described herein, no additional space is required.

[0090] In Figures 6 and 7, an embodiment of the optical detector 1 focusing on the flicker sensor is shown. Concerning the first sensors 21, the arrays 25 and the aperture sheet 3, in particular, the same as to Figures 4 and 5 may also apply to Figures 6 and 7.

[0091] In case the directions of sensitivity C of the first sensors 21 arranged around a center one of the first sensors 21 point outward, that is, away from the viewing direction D of the optical detector 1 as shown in Figure 2, the respective apertures 41, 42 increase a size requirement of the array 25. Thus , a distance between adj acent first sensors 21 within the arrays 25 is smaller than a distance between adj acent first sensors 21 of di f ferent arrays 25 . Hence , between the first sensors 21 of di f ferent arrays 25 there is some space available . In this space a second sensor 22 for flicker detection is located . The second sensor 22 may not be limited to a particular spectral range within the visible spectral range .

[0092] The second sensor 22 does not have its own aperture in the first layer 31 but uses the first apertures 41 of the adj acent first sensors 21 . According to Figure 6 , four of the first apertures 41 overlap with a light entrance face 20 of the second sensor 22 , seen in top view, and, hence , the light entrance face 20 partially overlaps with these four first apertures 41 .

[0093] Through these first apertures 41 , the second sensor 22 can detect light from directly above the second sensor 22 as well as over a large angular range , for example , up to an angle of total reflection of about 40 ° of incident light arriving at the aperture sheet 3 . Thus , the second sensor 22 can be sensitive over the full angular range also covered by all the first sensors 21 .

[0094] A distance between the arrays 21 and a si ze and / or a location of the second sensor 22 between the arrays 21 is chosen so that a distance between the respective first apertures 41 is at least 20 pm or is at least 50 pm or is at least 100 pm . For example , said distance is at most 90% or at most 80% of an extent of the second sensor 22 along the respective distance direction . Accordingly, a width of the remaining opaque region of the first layer 31 may be smaller than a width of the seconds sensor 22 along the same direction .

[0095] A si ze of the first apertures 41 of the adj acent first sensors 21 of the di f ferent arrays 25 and towards the second sensor 22 may be chosen so that a maximum angle of incidence of light onto the respective first sensors 21 corresponds to a critical angle for total reflection . Accordingly, even a more extended first aperture 41 would not allow light of smaller angles of incident to arrive at the respective first sensor 21 .

[0096] The second layer 42 next to the second sensor, 22 further comprises a flicker aperture 45 . The flicker aperture 45 partially covers the light entrance face 20 of the second sensor 22 . The light entrance face 20 may be arranged in parallel with the second layer 42 and, thus , with the flicker aperture 45 .

[0097] As an option, the base body 30 may be composed of a plurality of sub-sheets 301 , 302 . Between adj acent sub-sheets 301 , 302 , there can be an intermediate layer 33 comprising intermediate apertures 43 for the aperture stacks 44 assigned to the first sensors 21 . Edges of all the apertures 41 , 42 , 43 of one of the apertures stacks 44 may define a cone of the respective aperture stacks 44 . All the cones may widen in a direction away from the first sensors 21 . By means of the at least one intermediate layer 33 , optical cross talk between adj acent first sensors can be reduced . In principle , using more intermediate layers 33 layers may enable smaller distances between the first sensors 21 . For the seconds sensor 22 , there can be an additional flicker aperture 46 in the intermediate layer 43 . As shown in Figure 7 , the flicker aperture 45 and the additional flicker aperture 46 may be congruent or approximately congruent .

[0098] A distance between the second sensor 22 and the nearby first sensors 21 may be smaller than the distance between adj acent ones of the first sensors 21 within the arrays 25 . This is possible because the second sensor 22 does not need to have its own aperture in the first layer 31 .

[0099] The overall aperture sheet 3 may be of plane-parallel fashion, for example . The sub-sheets 301 , 302 may each have a thickness of at least 50 pm and / or of at most 300 pm, for example . The sub-sheets 301 , 302 may have di f ferent thicknesses wherein the first sub-sheet 301 next to the first layer 31 can be thicker than the second sub-sheet 302 next to the second layer 32 . For example , the thickness of the first sub-sheet 301 is between 110% and 200% or between 120% and 170% of the thickness of the second sub-sheet 302 . Other than shown in Figure 7 , there can be more than two of the subsheets and correspondingly more than one intermediate layer 33 .

[0100] Thus , because of the refractive index of the base body 30 the maximum possible angle of incidence is limited to about 40 ° . Hence , an area between the apertures 42 , 43 of the mid and bottom aperture layers 42 , 43 between the arrays 25 of the spectral channels have no optical relevance for the facet eye detection . This area can be used to detect a cross-talk signal with one additional unfiltered detector area, that is , the light entrance face 20 of the second sensor 22 . The additional detector 22 , without spectral filter, collects the rays passing the four corner apertures 41 of the upper aperture layer 31 . With an optimi zed aperture layer design, this covers and overlaps the full field of detection FOD of all the first sensors 21 .

[0101] In addition to the color filter 51 , there can be an infrared filter, not shown . By means of such an infrared filter, infrared radiation can be kept away especially from the second sensor 22 . For example , such an infrared filter is opaque above 780 nm until at least an absorption edge of the second sensor 22 which is , for example , around 1 . 1 pm .

[0102] As a further option, the processing unit 12 to synchroni ze the first sensors 21 to the flicker signal measured with the second sensor 22 is part of the optical sensor 12 . Hence , the optical sensor 12 may not need processor resources of the picture-recording device itsel f for synchroni zing data acquisition of the first sensors 21 with the flicker frequency of the ambient light .

[0103] Otherwise , the same as to Figures 1 to 5 may also apply to Figures 6 and 7 , and vice versa .

[0104] In Figure 8 it is shown that the flicker aperture 45 and the additional flicker aperture 46 does not need to be congruent . For example , the flicker aperture 45 can be larger than the additional flicker aperture 46 . Preferably, the flicker aperture 45 and the additional flicker aperture 46 are directly surrounded all around by the opaque material or the opaque layer sequence of the second layer 32 and the intermediate layer 33 .

[0105] Otherwise , the same as to Figures 1 to 7 may also apply to Figure 8 , and vice versa . In Figure 9 , some variants of the configuration of the second sensor 22 are illustrated . These di f ferent configurations can be used individually or in any combination in the optical detector 1 .

[0106] The second sensors 22 can use various numbers of the first apertures 41 . For example , the central second sensor 22A uses four of the first apertures 41 , similar to what is shown in Figure 6 . As an option, the second sensor 22A can be segmented, for example , into four segments corresponding to the four first apertures 41 . Optionally, electrical signals of the segments may be evaluated separately to get spatially resolve flicker information .

[0107] The second sensors 22D, 22E and 22 F each use two of the first apertures 41 wherein the second sensors 22E , 22 F are located between middle parts of the adj acent arrays 25 while the second sensors 22D are located at the corners of two marginal arrays 25 . Optionally, the second sensors 22D, 22 F may be segmented, too , analogously to the second sensor 22A.

[0108] The second sensors 22B, 220 use j ust one of the first apertures 41 . The second sensor 22B is located at an edge of the overall arrangement of the first sensors 21 while the second sensor 220 is located in a middle section of one of the marginal arrays 25 .

[0109] Optionally, the second sensors 22E , 22 F may not be centered between two adj acent ones of the first sensors 21 but may be shi fted along the edges of the adj acent arrays 25 so that these second sensors 22E , 22 F may use four of the first apertures 41 , too . Analogously, the second sensor 220 may be shifted along the marginal edge so that it may us two of the first apertures 41, for example. If more elongated second sensors 22C, 22E, 22F would be used, even more first apertures 41 may be involved.

[0110] Otherwise, the same as to Figures 1 to 8 may also apply to Figure 9, and vice versa.

[0111] Thus, various numbers of first apertures 41 and of aperture layers 31, 32, 33 may be utilized. From a single monochrome facet eye sensor with four surrounding flicker structures up to multi-spectral sensors with structures in between can be realized. A filter on the flicker sensor 22 may be used for infrared blocking. Various geometries of the flicker apertures 45, 46 and sensor geometries, compare Figure 9, are possible especially as long as it does not hamper the optical path of the spectral channels 25. The flicker sensor 22 may b split into segments. Various positions of the second sensor 22 in corners, borders or in between are possible, see also Figure 9. Overall flicker signal processing can be a sum of all the flicker sensors or the segments and only one modulator may be required, that is, a single flicker channel may be processed; otherwise, separated signal processing is enabled using a plurality of modulators that give segment information about the flicker in a scenery. Structured thin film diffusers 55 can be used so that no filter and no diffuser may be present on the flicker sensor 22 in order to decrease the internal cross talk because of high absorption as the light entrance face 20 of the second sensor 22 may have high absorption similar to the aperture layers 31, 32, 33. In Figure 10, a block diagram of a manufacturing method is shown. In method step Ml, a substrate 53 is provided. The substrate 53 carries the first sensors 21 and the second sensor 22. The substrate can be a permanent substrate present in the finished optical sensor or can be a temporal substrate removed later on. According to method step M2, the aperture sheet 3 is provided.

[0112] In method step M3, the aperture sheet 3 is attached at the substrate 53, for example, by gluing.

[0113] The apertures sheet 3 may be produced using lithographic techniques, for example. Thus, a positioning tolerance of the apertures 41, 42, 43, 45, 46 relative to one another may be relatively small, like at most 5 pm or at most 1 pm.

[0114] On the other hand, positioning tolerances of the first and second sensors 21, 22 relative to one another and of the apertures sheet 3 relative to the substrate 53 may be relatively large, for example, at least 10 pm or at least 20 pm or at least 30 pm.

[0115] For this reason, edge lengths of the sensor chips 21, 22 are, for example, at least twice the latter positioning tolerance larger than the second apertures 42 and the at least one flicker aperture 45. For example, if the positioning tolerance of the first sensors 21 relative to one another and of the apertures sheet 3 relative to the substrate 53 is T and the diameter of the second apertures 42 is D, then it applies E > D + 2T. Hence, it can be assured that the second apertures 42 always are located on the assigned first sensors 21. The same applies analogously for the second sensor 22 and the flicker aperture 45. For example , the second sensor 22 has an edge length of at least 200 pm and of at most 300 pm . For example , the first sensor 21 has an edge length of at least 100 pm and of at mo st 200 pm .

[0116] Otherwise , the same as to Figures 1 to 9 may also apply to Figure 10 , and vice versa .

[0117] The components shown in the figures follow, unless indicated otherwise , exemplarily in the speci fied sequence directly one on top of the other . Components which are not in contact in the figures are exemplarily spaced apart from one another . I f lines are drawn parallel to one another, the corresponding surfaces may be oriented in parallel with one another . Likewise , unless indicated otherwise , the positions of the drawn components relative to one another are correctly reproduced in the figures .

[0118] The invention described here is not restricted by the description on the basis of the exemplary embodiments . Rather, the invention encompasses any new feature and also any combination of features , which includes in particular any combination of features in the patent claims , even i f this feature or this combination itsel f is not explicitly speci fied in the patent claims or exemplary embodiments .

[0119] This patent application claims the priority of German patent application 10 2024 110 765 . 0 , the disclosure content of which is hereby incorporated by reference . References

[0120] I optical detector

[0121] 20 light entrance face

[0122] 21 first sensor for generating a color signal

[0123] 22 second sensor for generating a flicker signal

[0124] 25 array of first sensors

[0125] 3 aperture sheet

[0126] 30 base body

[0127] 301 first sub-sheet

[0128] 302 second sub-sheet

[0129] 31 first layer

[0130] 32 second layer

[0131] 33 intermediate layer

[0132] 34 cover layer

[0133] 41 first aperture

[0134] 42 second aperture

[0135] 43 intermediate aperture

[0136] 44 aperture stack

[0137] 45 flicker aperture

[0138] 46 additional flicker aperture

[0139] 51 color filter

[0140] 52 detection timer

[0141] 53 substrate

[0142] 54 adhesive

[0143] 55 di f fusor

[0144] 9 modi fied optical sensor

[0145] 10 picture-recording device

[0146] I I camera system

[0147] 12 processing unit

[0148] 13 cover glass

[0149] A area of color detection

[0150] C direction of sensitivity of the first sensor D viewing direction of the optical detector

[0151] F direction of sensitivity of the second sensor

[0152] FOD field of detection of the optical detector

[0153] FOV field of view of the camera system L critical entrance line

[0154] M method step

[0155] P viewing direction of the camera system

[0156] S line of sight

Claims

Claims1. An optical detector (1) comprising:- an aperture sheet (3) comprising a first layer (31) and a second layer (32) ,- a plurality of first sensors (21) being located at the second layer (32) , and- a second sensor (22) having a light entrance face (20) and also being located at the second layer (32) , wherein- for each one of the first sensors (21) there is a first aperture (41) and a second aperture (42) in the first layer (31) and in the second layer (32) , respectively, so that for each one of the first sensors (21) there is an aperture stack (44) defining a direction of sensitivity (C) of the respective one of the first sensors (21) , and- the second sensor (22) has lines of sight (S) through at least one of the first apertures (41) and has a further line of sight perpendicular with the light entrance face (20) .

2. The optical detector (1) according to the preceding claim, further comprising a detection timer (52) , wherein- there is exactly one of the aperture stacks (44) per first sensor (21) ,- for each one of the first sensors (21) , there is a color filter (51) so that the first sensors (21) are sensitive only in a sub-range of the visible spectral range,- the second sensor (22) is sensitive in the overall visible spectral range,- the second sensor (22) is configured to produce a timedependent flicker signal, and- the detection timer (52) is configured to synchronizedetection time intervals of the first sensors (21) with the flicker signal.

3. The optical detector (1) according to any one of the preceding claims, wherein the first layer (31) is free of an aperture exclusively for the second sensor (22) and not being part of at least one of the aperture stacks (44) so that the second sensor (22) has the lines of sight (S) exclusively through the at least one of the first apertures (41) , and wherein the second layer (32) comprises a flicker aperture (45) assigned exclusively to the second sensor (22) .

4. The optical detector (1) according to the preceding claim, wherein the flicker aperture (45) partially covers the light entrance face (20) of the second sensor (22) , seen in top view of the light entrance face (20) .

5. The optical detector (1) according to any one of the preceding claims, wherein the light entrance face (20) of the second sensor (22) partially overlaps with the at least one of the first apertures (42) defining the lines of sight (S) , seen in top view of the light entrance face (20) .

6. The optical detector (1) according to any one of the preceding claims, wherein the aperture sheet (3) comprises one or a plurality of intermediate layers (33) located between the first layer (31) and the second layer (32) , wherein the intermediate layer (33) or each one of the intermediate layers (33) comprise (s) an intermediate aperture (43) exclusively assigned to one of the aperture stacks (44) ,and wherein the intermediate layer (33) or each one of the intermediate layers (33) comprise (s) an additional flicker aperture (46) exclusively assigned to the second sensor (22) .

7. The optical detector (1) according to the preceding claim, wherein the additional flicker aperture (s) (46) of the intermediate layer (s) (43) and the flicker aperture (45) of the second layer (42) are congruent, or the flicker aperture (45) is larger than the additional flicker aperture (s) (46) .

8. The optical detector (1) according to any one of the two preceding claims, wherein there is the exactly one intermediate layer (33) or there are two or three of the intermediate layers (33) .

9. The optical detector (1) according to any one of the preceding claims, wherein each one of the aperture stacks (44) widens along the direction of sensitivity (C) and away from the second layer (32) .

10. The optical detector (1) according to any one of the preceding claims, wherein the first sensors (21) are arranged in a plurality of arrays (25) , each one of the arrays (25) being sensitive for a specific color and including some of the first sensors (21) , wherein a number of the first sensors (21) in each one of the arrays (25) is the same as a number of the directions of sensitivity (C) of the respective one of the arrays (25) , said directions of sensitivity (C) differ pairwisely.

11. The optical detector (1) according to the preceding claim, wherein a distance between adjacent ones of the first sensors (21) within the arrays (25) is smaller than a distance between adjacent ones of the arrays (25) , seen in top view of the second layer (32) , wherein the second sensor (22) is located between the arrays (25) .

12. The optical detector (1) according to any one of the preceding claims, wherein the number of the first sensors (21) in each one of the arrays (25) is at least four and is at most 25.

13. The optical detector (1) according to any one of the preceding claims, comprising a plurality of the second sensors (22) , wherein the second sensors (22) have different directions of sensitivity (F) .

14. The optical detector (1) according to any one of the preceding claims, wherein the aperture sheet (3) comprises a continuous, hole- free base body (30) , wherein the first layer (31) and the second layer (32) are applied on main sides of the base body (30) , and wherein the base body (30) has a refractive index of at least 1.4 and of at most 1.8 at 532 nm and at 300 K.

15. A picture-recording device (10) comprising:- an optical detector (1) of one of the preceding claims,- a camera system configured to take pictures in the visible spectral range, and- a processing unit (12) , wherein the processing unit (12) is configured to calculate a white balancing for the pictures taken by the camera system using data from the optical detector (1) .

16. A manufacturing method for producing an optical detector (1) of one of claims 1 to 14 comprising:- providing a substrate (53) carrying the first sensors (21) and the second sensor (22) , - providing the aperture sheet (3) having the first layer(31) and the second layer (32) , and- attaching the aperture sheet (3) at the substrate (53) .

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